Reactions of Molybdenum and Tungsten Phosphenium Complexes with Sulfur and Selenium

The reactions of the phosphane [(Me3Si)2N](Ph)PCl with NaCpMo(CO)3 and NaCpW(CO)3 give the respective metallophosphenium complexes Cp(CO)2M{P(Ph)[N(SiMe3)2]} (M = Mo (4a), W (4b)). The subsequent reactions of 4a,b with S and Se produce unexpectedly different products: Cp(CO)2(S)M{P(Ph)[N(SiMe3)2]} (M = Mo (7a)); Cp(CO)2MSP(Ph)[N(SiMe3)2] (M = W (7b)); Cp(CO)2MSeP(Ph)[N(SiMe3)2] (M = Mo (8a), W (8b)). The compounds have been fully characterized by elemental analyses and spectroscopic data, and the molecular structures of 4a, 7a,b, and 8a have been determined by single-crystal X-ray diffraction techniques. The molecular structure of 7a displays a long, terminal Mo−S bond, while 7b and 8a contain M−E−P three-membered rings.